Why cant an eletric shower be fed from both hot and cold supplies (maybe pre mixed with a thermostatic valve) in order to reduce the heating load required by the electric shower itself? The aim being to attain a hotter shower at an increased flow rate compared to an electric shower fed by a cold mains supply only. Answers such as "it is not in the book" nor "just cannot be done" will be kindly ignored.
why cant you get a bigger electric shower ?? 10.5 kw is the biggest i think, decent flow rate for a electric model, as regards blended water the showers have a over temp to stop scalding, if you want to have a mixer shower just get one and forget the electric !
A bigger shower (10kw) needs a bigger cable than the 10mm that I have used. I do not want to use a mixer shower because I rarely have hot water in the immersion tank. I would like the flexibility of having an electric shower with a cold feed but use the warmer than mains water from an otherwise cool immersion tank. My question is rearely why can it not be done?
I was thinking about the real world rather than the marketed world. When the mains supply is really cold the flow rate drops with an electric shower. Surely by mixing in some cool tank water rather than all colder mains water, a better flow rate can be achieved without resorting to a hugely powerful kw rating. THINK about the limits that you choose to work within.
You dont need a bigger cable than 10mm. Dont electric showers need a certain amount of pressure. Give it ago and report back.
1omm cable will be no problem and you can get 10.5 kw showers to give 10lts a min, you could use stored water which may be warmer than mains but you would have to pump it into the shower to get the required pressure input to lift the pressure switch to allow the shower to work and elements to come on to heat water
Freedom, stop embarrassing yourself, stop displaying your stupidity with such enthusiasm, it's cringe inducing.
Freedom (please don't tell me you're Scottish), the reasons have been given above: (a) you need 'mains' pressure to 'drive' an electric shower (which you wouldn't get from a hot cylinder), and (b) if the water being delivered was too warm, the shower would overheat. That's the 'real world'.
This is actually a sensible question, the answers have been ridiculing the poster without cause. Its possible to have a mains pressure hot cylinder, so that's not a reason not to do this. If the shower would overheat with a warm feed, then its thermostat must be faulty. Are you saying it has no temp regulation. I too want to have a hot feed to a shower - here's why... I have solar panels and want to better use the energy created. I could heat hot water (currently no HW storage in house, only oil fired on demand type heater) and could feed that hot water to an electric shower. When there's no sun the shower would get a cold mains pressure feed, and heat that as normal. When there's sun, there's stored hot water at mains pressure, which goes to the shower and it either tops up the temp, or doesn't add any heat to water that's hot enough. All seems feasible, just need to find the right shower unit to do the job.
Simple , in goes against manufacturers installation instructions! So a nono. Would prob be same with water bye laws, rant over.
Being against a manufacturers installation instructions might preclude one specific model or make, but not the principle. That something "might" be against a bye-law sounds like as excuse not to do it, not a reason. I'm seeking a manufacturer that wants to solve a problem, not find an excuse not to.
I for one agree with the priciple of cold water storage tank supplying electric shower. Karcher pressure washers are able to run from water-butt, so no reason why an electric shower couldn't run(if designed to) from a CWT. And yes, save money. Less power to heat the water because the tank water will not be as cold. More pressure because mains needs slowing anyway,to get the heat, and shower internal pump can produce pressure without the volume just like a karcher pw does. That is the only downside, a pump in the shower unit, possibly noisy. Mr. HandyAndy - Really
I was curious about this myself. I knew I had a good hot water supply pressure from my cylinder. I knew the risk is that if the cylinder water got too hot then shower cannot cool it. So just setup the cylinder heating system to have the water temperature in cylinder luke warm only. So I tried it. Why the hell not. Supplied my electric Triton T90si 8.5 KW from my hot water cylinder. Took 10 minutes to switch the pipes over. I then was able to run the shower at maximum pressure and a reduced heater setting. Worked a treat. You can adjust the shower heater setting depending on the water temprature in the cylinder. If the cylinder water is hot enough the the electric shower heater setting can be set to cold and you still get max pressure showering with the temprature of the water in the cylinder. The trick here is to set your cylinder thermostat so that it will not to heat the water too hot. Just luke warm. (Remember the electric shower cannot cool water) I have my cylinder heater on a daily timer. Heats the cylinder water for 30 mins every 24 hours. This keeps the cylinder water luke warm. Now I have full pressure from my electric shower even in very cold weather. And I'm using less power to run the electric shower.
Temperature control is the traditional strategy for reducing the risk of legionella in water systems. Cold water systems should be maintained, where possible, at a temperature below 20 °C. Hot water should be stored at least at 60 °C and distributed so that it reaches a temperature of 50 °C (55 °C in healthcare premises) I am not sure how this applies to your system but this is what the HSE requires us in the trade to do. A pumped electric shower may be the way to go, as it will take its own feed from the cold storage so ambient water temperature, and you can then set the hot water cylinder to the correct temperature.
As long as the water inlet to the shower is at high pressure then it is fine. Use a blending valve on the inlet to the shower and adjust to get the optimum. You may get a higher flow rate from the shower.
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